1. Field of the Invention
The invention relates to a leaf spring suspension assembly for an automotive vehicle. More particularly, the invention relates to a leaf spring suspension having a pin preventing relative transverse displacement between the sleeves.
2. Description of the Related Art
Automotive vehicles typically include a suspension for coupling a wheel to a vehicle body. Suspensions serve a dual purpose of contributing to the car's handling and braking for good active safety and driving pleasure, and keeping vehicle occupants comfortable and reasonably isolated from road noise, bumps, and vibrations. All suspensions utilize some form of a spring to absorb impact associated with the wheel rolling over a road. For example, a coil suspension uses a helical coil spring that is continuously compressed between a fixed point on the vehicle frame and a pivotable linkage in the suspension.
Another type of suspension is a leaf spring suspension, which utilizes a slender arc-shaped length of spring steel having a generally rectangular cross section. The center of the arc is configured to support the axle, while tie holes are provided at opposite ends for attaching to the vehicle body. A leaf spring suspension may include several leaves clamped together in a stack having several layers. A multilayer leaf suspension typically uses systematically shorter leaves with the longest leaf being directly coupled to the vehicle body. Conventional leaf spring suspensions are not well suited to handling transverse loads on the vehicle, such as those experienced during a high speed turn. The transverse loading may cause the leaves to separate or “splay” relative to each other, which then adversely affects the handling characteristics of the suspension. It is known to insert a pin through a bore formed in each leaf of the suspension in order to prevent relative transverse movement between the leaves. However, providing a bore in the leaf springs introduces an undesired stress concentration, particularly in the longest leaf that is directly coupled to the vehicle.
Accordingly, it remains desirable to provide a leaf suspension design that prevents separation or splaying between the leaf springs during transverse loading of the suspension and at the same time minimizes or eliminates undesired stress concentrations in the leaf that is directly coupled to the vehicle frame.